Traditionally, with respect to a projection-type display system, it is proposed in Japanese Patent Publication No. JP-A-8-168039 that “an inspection pattern is combined with video signals 810 and 820 and projected onto a screen 7 from two projectors 110 and 120. The position of this inspection pattern is detected by an image sensor 60, and on the basis of the detected position, a displacement quantity analyzing unit 50 calculates a positional shift of the projection position by image processing and so on, as a displacement quantity. In accordance with this displacement quantity of the projection position, feedback is given to display position adjustment mechanism units 210 and 220 and the positional shift is automatically corrected optically and mechanically. Thus, pixel alignment of plural projectors to realize high definition can be carried out easily and accurately,” as a technique for the purpose of “providing a projection-type display system that facilitates pixel alignment in order to achieve light weight and high definition, and a projection position adjusting method for the same.”
With respect to a multi-screen display apparatus, it is proposed in Japanese Patent Publication No. JP-A-2000-241879 that “an automatic screen position adjustment device for a multi-screen display apparatus including a reflection mirror and a light detection sensor arranged for common use at a seam part of screens that are next to each other, wherein light projected from projectors that are next to each other is reflected by the reflection mirror and a detection signal obtained by detecting the reflected light by the light sensor is used to automatically adjust the screen position of video light projected from the projectors, to a predetermined position,” as a technique to cope with a problem that “traditionally, in a multi-screen display apparatus, a person skilled in the art takes a long time to make screen position adjustment in order to match seams of videos displayed on screens that are next to each other.”
With respect to a table-type display, it is proposed in Japanese Patent Publication No. JP-A-2006-251604 that “an image sensor 51 is caused to operate first, and an image pickup signal from the image sensor 51 is taken into an image pickup data processing unit 63. The image pickup data processing unit 63 detects the coordinate position of a mark MA on a screen 40 and updates a position conversion table in a position data conversion table unit 64. Thus, initial processing is complete. In this state, when an image signal is inputted to an image data processing unit 61 from outside, the image data processing unit 61 carries out coordinate conversion for the image signal by referring to the position conversion table in the position data conversion table unit 64 via a control unit 65. Thus, image light modulated by light valves 35a, 35b and 35c is projected to perfectly fit in a display area 41 of the screen 40,” as a technique for the purpose of “providing a table-type display that enables accurate projection of an image at a target position on a screen.”
Traditionally, if a multi-screen system is formed by using plural projectors, the person who installs the system manually confirms and adjusts the positional relation between each projector and screen, lens power, defocusing and so on. This requires a considerable amount of time and effort.
With respect to this point, it is described in JP-A-8-168039 that pixel alignment of plural projectors is carried out by using the image sensor 60. However, this achieves higher definition of a single screen and no specific measures are described for positional alignment of projectors in a multi-screen system.
In JP-A-2000-241879, the reflection mirror and the light detection sensor must be arranged at the seam part of screens. Additional cost and work are required for this.
In JP-A-2006-251604, since coordinate conversion of an image signal is carried out to match the mark MA on the screen 40, the mark MA must be provided in advance on the screen 40. This poses a problem in terms of versatility.